Many minerals useful for treating mineral deficiency are only soluble as metal ions, which in general are irritating to tissues and have an unpleasant taste. Metal complexes have been used instead to address this problem.
Metal complexes, usually having a high turbidity point and a low acid dissociation rate, are unstable in neutral or acidic conditions desired for oral and intramuscular applications. As such, they are typically formulated in a basic solution. For example, Venofer, an iron sucrose commercial product that must only be administered via the intravenous route, has a pH value as high as 11, making it unsuitable for beverages and pharmaceutical formulations other than intravenous injections.
There is a need to develop metal complexes that are stable in neutral or acidic conditions.